Apparatus for interval feed and jet screening of stock



17, 1956 J. o. MQCRYSTLE ET AL 0,

APPARATUS FOR INTERVAL FEED AND JET SCREENING OF STOCK Filed Oct. 4, 1954 w i r.. v JIHMMWHMT. IIIIN \\L APPARATUS FOR INTERVAL FEED AND JET SCREENING OF STOCK Application October 4, 1954, Serial No. 460,068

8 Claims. (CI. 92-30) This invention relates generally to pulp and paper manufacture and is directed more particularly to apparatus for the preparation of fibrous stock for pulp and paper making and the like.

The principal object of the invention is the provision of novel apparatus for the interval feed of fibrous stock to flat screen apparatus such as disclosed in the U. S. patent to Packer No. 669,933 of March 12, 1901, and jet screening the same.

It is well known that in the operation of a so-called flat screen apparatus of the type referred to there is an inherent tendency toward a dewatering action of the stock on the screen plates which results in the formation of a mat of fibers on the screen plates during the screening operation. With a certain maximum consistency of stock being screened and depending upon the characteristics of the fibers of the stock, the screen apparatus ceases to function with a screening action. To obviate this condition, it has been necessary to operate with low stock consistencies in order to obtain the maximum capacity and dirt removal.

According to the novel features of this invention, apparatus is provided for use with a fiat screen whereby stock of relatively greater consistency may be screened with a less number of screen plates without sacrifice of capacity and with improved dirt count of the screened stock.

The novel apparatus of the invention is constructed and arranged whereby stock is fed and water is discharged simultaneously to a flat screen at intervals or spaced points along and angularly relative to the screen plates of the vat. In this way, there are jets which sweep over and across the faces of all the plates which results in the use of stock of greater consistency than heretofore pos sible with the mixing of stock and water whereby individual fibers pass through the screen plate apertures and are separated in suspension.

The foregoing interval feeding of stock is to be distinguished from the prior art practice whereby stock is admitted at the inflow end of the vat and flows along all of the plates of the vat.

By means of the novel apparatus of the invention, dirt is maintained above the plates to a greater degree than formerly, the tendency for fibers to form a mat or clots on the screen plates so that dirt is held on the plates is obviated and dirt is swept at high velocity towards the throw-out end of the vat machine. As one advantage, the apparatus makes it possible to operate a screen at its maximum efficiency as distinguished from prior art practice where the screen at its head end is overloaded with a decreasing load therealong.

As an example, With a certain stock it has been necessary heretofore to operate with a consistency as low as from two-tenths to six-tenths of one percent. With the apparatus ofthis invention, it has been possible to operate with a consistency as high as one percent and above with maximum tonnage and cleanliness. The water discharged may have a pressure of from 30 to lbs. per square inch and is discharged by controlled flow jets.

The novel apparatus includes ingeneral an elongated conduit adapted to extend along and above a screen vat which is provided with separate stock and water passageways having separate inlets with downwardly extending spouts at intervals along the conduit which are provided at lower ends with transversely extending stock and water discharge means for discharging stock and water simultaneously and in adjacency at intervals or spaced points along the vat screens.

All of the above objects we accomplish by means of such structure and relative arrangements of parts thereof, as will fully appear by a perusal of the description below and by various specific features which will be hereinafter set forth.

To the above cited and other ends and with the foregoing and various other novel features and advantages and other objects of our invention as will become more readil'y apparent as the description proceeds, our invention consists in certain novel features of constmction and in the combination and arrangement of parts as will be here inafter more particularly pointed out in the claims hereunto annexed and more fully described and referred to in connection with the accompanying drawings wherein:

Fig. 1 is a side elevational view of the apparatus of the invention shown as associated with the vat of a screen apparatus;

Fig. 2 is a sectional plan view on the line 22 of Fig. 1;

Fig. 3 is a sectional elevational view on the line 3-3 of Fig. 1;

Fig. 4 is a front elevational view of one of the discharge spout members of the apparatus shown in Fig. 1;

Fig. 5' is a side elevational view of the discharge member shown in Fig. 4; and

Fig. 6 is a partial sectional plan view on the line 66 of Fig. 4.

Referring now to the drawings more in detail, the invention will be fully described.

The upper portion of a screen vat is shown at 2 which has end and side walls 4 and 6. Screen plates are represented by 8. The vat and its screen plates are similar to that shown in the U. S. patent to Packer No. 669,933 of March 12, 1901.

An elongated conduit it) is provided which has downwardly depending discharge spouts i2 and 14 spaced at intervals therealon g.

The conduit lit and spouts will preferably be formed from welded together sheet metal and may be supported above the vat in any convenient manner as by laterally extending brackets 16 engaging the side walls is of the vat.

The conduit may be rectangular in cross section to have lower, side and upper walls 18, 2b and 22 and said conduit may be in any desired number of sections joined together by flanges 24 which are secured together.

An entrance end of the conduit at the left in Fig. 1 has a stock inlet 26 to receive stock from such a source as may be desired and a separate water inlet 23.

An elongated inner wall 38 extends along the conduit between opposite side walls and the upper and lower walls thereof to divide the conduit into a water passageway 34 and a stock passageway 36 longitudinally of the conduit. The stock inlet 26 is in communication with passageway 36 and the water inlet 28 is in communication with the water passageway 36.

The spouts 12 as in Figs. 4 and 5 have a forward wall 38, rear wall 40 and side walls 42. The said rear wall curves at til forwardly at its lower end and diverges upwardly relative to said lower end, as shown in Fig. 5. The side walls 42 diverge relative to one another to the upper ends as shown. Screws Stfextend forwardly from wall 38 of the spout and'through the slots of the brackets 48; Clamp nuts 52 on the screws 50 engage the brackets 48 and hold the gate in adjusted position. The gate 46 may carry a packing 46 for engaging forward wall 38 of the spout 12. V I

The bottom wall 18 of the conduit isprovided with openings 18- therethrough, see Fig. 6, whereby stock flowing along the'conduit flows downwardly into the spouts 12 from whence it is discharged forwardly through the slots 44 thereof and into the screen plates as indicated by S, in Fig; l.

Pipes 60 extend downwardly from the bottom wall of the conduit and are in communication with the water passageway 34. These pipes 60 are preferably within the spouts 12 and are connected at lower ends to transverse distributing pipes 62. Said pipes 62 are adjacent the forward walls 38-of the spouts and discharge nozzles 64 on the face of wall 38 are in communication with the pipes 62 for discharging water. There may be as many nozzles 64 as desired and they will be arranged to discharge water forwardly and downwardly onto the screen plates as indicated by W in Fig. 1.

Over the most forward spout 12 an upper plate 22 blocks offthe stock passageway so that stock does'not flow to the spout 14. Said spout 14 includes a downwardly extending pipe 68 in communication with the water passageway and with a transverse elongated lower pipe 70 which is provided with nozzles similarly to the nozzles 64 of spouts 12.

It will be observed that the apparatus is adapted to feed stock' and discharge water at intervals along a screen vat into and angularly relative to the screen plates thereof and that the rate of discharge of stock is adjustable by means of a gate all to the end that maximum efficiency maybe obtained.

There may be as many spouts 12 and 14 as may be desired, it being understood that it is desired to feed stock and discharge water at intervals along the screen plates of the vat, The rate of stock flow from the spouts may be alike or may differ and the water discharge and pressure employed may be alike or different relative to plural spouts, all as may be desired.

As a particular feature, the spouts are so formed that stock is directed forwardly and angularly relative to the screen plates but other means may be employed. Also various means may be employed for discharging water forwardly and angularly.

There may be any number of combination spouts for discharging stock and water simultaneously or any desired number of combination spouts and water discharging spouts depending upon the screen vat, particular stock to be screened, and other variables.

The invention may be embodied in other specific forms without departing from the essential characteristics thereof. Hence, the present embodiments are therefore to be considered in all respects merely as being illustrative and not as being restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all modifications and variations as fall within the meaning and purview and range of equivalency of the appended claims are therefore intended to be embraced therein.

What it isdesired to claim and secure by Letters Patent of the United States is:

1. Apparatus for interval feed and jet screening of stock comprising in combination, an elongated conduit for locating over a screen vat having screen plates and having a forward end, said conduit being provided with separate stock and water passageways therealong having separate inlets at rear ends thereof, spouts spaced at intervals along and depending from said conduit in communication with said stock passageway and provided at, lower, ends with stock discharge means and separate water discharge means, connecting means carried by said spouts in communication with said water passageway and said water discharge means.

2. Apparatus set forth in claim'l wherein said stock and water discharge means are in adjacency arranged and disposed to discharge stock and water transversely of and towards the forward end of said conduit and angularly relative to screen plates therebelow.

3. Apparatus set forth in claim 1 wherein said connecting means includes depending hollow members within said spouts connected at upper ends to said water passageway and having transverse perforated hollow members at lower ends thereof connected as said water discharge means. 7 g j V V I 4. Apparatus for interval feed and jet screening of stock comprising in combination, an elongated conduit having rear and forward ends and being divided transversely forming separate elongated stock and water passageways therealong having separate inlets at rear'ends thereof, separate combination spouts depending from said conduit at intervals longitudinally thereof connected at upper ends to the stock passageway thereof, water conducting means connected at upper ends to said Water passageway and depending downwardly from said conduit adjacent said spouts, said spouts flaring outwardly and downwardly and transversely relative to the conduit and having elongated stock discharge means at lower ends thereof arranged transversely to the conduit, to discharge stock towards the forward end of the conduit, said water conducting means discharging means includes longitudinally spaced jets having discharge orifices.

' 7. Apparatus for interval feed and jet screening of stock comprising in combination, an elongated conduit for locating over a screen vat having screen plates, said conduit being provided with separate stock and water passageways therealong having separate inlets, a plurality of spouts spaced at intervals along and depending from said conduit, lower portions of said spouts extending transversely of and below said conduit for overlying screens, of a screen vat, one of said spouts having separate stock and water discharge means at the lower portion thereof in separate communication with the stock and water passageways of the conduit respectively, and another of said spouts having water discharge means at the lower portion thereof in communication with the said water passageway.

8. Apparatus for the preparation of paper'makingstoc comprising, an elongated conduit having forward and rear ends and being divided transversely forming separate elongated stock and water passageways therealong having separate inlets at rear ends thereof, a plurality of separate combination spouts depending from said conduit at'inter vals longitudinally thereof connected at upper ends'to the stock passageway thereof, water conducting means connected at upper ends to the water passageway and.dependingdownwardly from said conduit and adjacent to said spouts, said spoutsfiaring outwardly and downwardly and transversely relative to said conduit and having stock discharge means at lower ends thereof arranged to discharge References Cited in the file of this patent stock towards the forward end of said conduit, the water UNITED STATES PATENTS conducting means havrng water drscharglng means adjacent the stock discharge means, and water discharge means 19 19 201 Clements July 25, 1933 spaced from said spouts and depending from said conduit 5 1,951,017 Hatch 1934 and having means at the lower end thereof for discharg- 2,608,910 Mccrystle P 1952 ing water towards the forward end of said conduit. 

1. APPARATUS FOR INTERVAL FEED AND JET SCREENING OF STOCK COMPRISING IN COMBINATION, AN ELONGATED CONDUIT FOR LOCATING OVER SCREEN VAT HAVING SCREEN PLATES AND HAVING A FORWARD END, SAID CONDUIT BEING PROVIDED WITH SEPARATE STOCK AND WATER PASSAGEWAYS THEREALONG HAVING SEPARATE INLETS AT REAR ENDS THEREOF, SPOUTS SPACED AT INTERVALS ALONG AND DEPENDING FROM SAID CONDUIT IN COMMUNICATION WITH SAID STOCK PASSAGEWAY AND PROVIDED AT LOWER ENDS WITH STOCK DISCHARGE MEANS AND SEPARATE WATER DISCHARGE MEANS, CONNECTING MEANS CARRIED BY SAID SPOUTS IN COMMUNICATION WITH SAID WATER PASSAGEWAY AND SAID WATER DISCHARGE MEANS. 